Axle housing



Sept. 6, 1949. L. R. BUCKENDALE I AXLE HOUSING 3 Sheets-Sheet 1 Filed Sept. 2, 1944 w a y W W e M; u ww 5 w A e d w M W W I I I I l I I I I I I I I I I I I I I I I l l I I I l l l l I I l I I I I! a L MW m MN h mm wv /I w 4 c ll. k Q o w an L. R. BUCKENDALE 2,480,833

' AXLE nousme Sept. 6, 1949.

3 Sheets-Sheet 2 Filed Sept. 2, 1944 Lawrence 1?. flue/renoa/e L. R. BUCKENDALE Sept. 6, 1949.

AXLE HOUS ING Filed Sept. 2, 1944 3 Sheets-Sheet 5 Patented Sept. 6, l94

AXLE HOUSING Lawrence R. Buckendale, Detroit, Mich.,' assignor to The Timken-Detroit Axle Company, Detroit, Mich., a corporation of Ohio Application September 2, 1944, Serial No. 552,507

9 Claims.

This invention relates to improvements in axle housings, and has particular reference to axle 'United States Letters Patents Nos. 1,108,114 to Alden and 2,204,287 to Wilber.

Housings of the above-identified type usually comprise opposed welded channel members previously stamped or pressed to provide an enlarged center portion surrounding a space for receiving differential gearings with-integral substantially straight portions extending from either side of the center portion toward the respective wheels.

- In such axle housings, it has been found necessary to secure reinforcing flange rings to housing flanges at opposite sides of the differential gear space for attachment of the differential bowl and the differential gear carrier. These reinforcement rings have usually been welded onto the housing, and were considered necessary because housing side flanges formed during the usual stamping or pressing operations were too weak for bolting or otherwise attaching the differential gear'carrier or the differential bowl.

These welded-on flange ring reinforcements have given considerable trouble in actual practice, primarily I have discovered because they are not secured to the adjacent housing flanges uniformly throughout their entire extent. As a result, localized stresses develop [causing fractures or other defects in the regions where attachment of the flange ring to the housing is weakest, resulting in axle housing failures and consequent more serious injury to the live axle parts carried thereby. Welding these flange rings to the housing represents the best known manner of attempting to obtain the desired uniform attachment, but I have discovered that even these welding operations do not reliably provide the optimum bond between the flange ring and housing, although welding is more satisfactory than bolting, rivet ing and the like.

The present invention contemplates elimination of this difficulty by forming the axle housing center section with relatively thick integral side flanges which contain sufficient metal and are of sufficient rigidity and strength to enable the differential bowl and the differential gear carrier to be boltedor welded directly thereto, and this is a primary object of the present invention.

Also, in thistype of axle housing, difficulty has been experienced 'in obtaining reliable support for the wheel bearing sleeves. Wilber, above-mentioned, formed his wheel bearing sleeves integral with separate housing end-sections which were butt-welded to the ends of the'center-section of of the axle housing. While this arrangement has been found satisfactory for many purposes, the present invention contemplates what I feel to be an improvement in this respect by forming thick, sturdy housing sleeves bosses intergral with, or suitably fixedly secured to, the opposite ends of the axle housing center section these housing sleeve bosses being of sufficient rigidity and strength and of suflicient axial extent 'to-provide unit support for the overhanging wheel bearing sleeves shrunk or otherwise fitted thereinto; and this is a further major object of my invention. l

The above and other phases of the invention will be explicitly described in the forthcoming specification wherein-several embodiments of the invention which are particularly adapted to commercial building or axle housings of this type will be herein described and claimed.

It is a further important object of the invention therefore to provide a novel forged axle housing having a combination of thickened integral side flanges at the center section for supporting a differential gear carrierand a differential bowl and having thickened bosses providing unit supports for wheel bearing sleeves.

It is a further object of the present invention to provide a novel axle housing which is an integral structure insofar as practical manufacturing considerations permit. v

A further object resides in the provision of a novel forged axle housing in which the minimum practical amount of fabrication by welding is employed. 7

A still further object resides in the provision of an improved forged axle housing, the center section of which has novel integrally thickened or stoved-up side flanges.

A further, object of the invention is to provide an improved axle housing having novel integral sto'ved-up spring seat portions of adequate area for attachment of the springs, I v

An additional object resides in the 'provision of an improved forged axle housing having wheel bearing sleeves mounted in special sturdy housing sleeve bosses at the ends of the housing center section. f

Another object resides 'in the provision of a novel axle housing having thickened housing sleeve bosses} integrally forged at the housing center sectionends. 1 j

Yet another object rsid$ inthe provision of 3 an improved axle housing having housing sleeve bosses integrally forged at the housing center section ends in which the rectangular cross section of the center section is reduced to the circular cross section of the sleeve boss in an improved manner.

It is also anobjeet ofcthe invention to provide an improved ans iioiisiiig hatingaberiter section provided with bolting or attachment flanges and spring seats, housing sleeve boss portions and wheel bearing sleeve portions in which the maximum number of such portions are integrally formed from the minimunr practical number of preliminary blanks by suitablamachineiorging operations.

A further object of the invention is to provide an improved machine forged aisle Housing having a thickened end boss for receiving a wheel bearing spindle or sleeve, siaid boss providing a unit support-for said sleeve suflicierrt tor adequate suprq hereo b re son ie di r construction Pursuant .togthis-zolqiect the boss may be integral with the axle-housing or fixed thereto.

Another; ob je ct residess'ln thelprovision of an improved aigle; housing in-which .a heavy, rigid strongintegraL side; f lange-.is provided for the support of adifierential carrier.

, Other objects and. advantages willbeapparent from i the 1 following; description and appended claims connection Jwith the accompanying drawingsin whlch:,; 1 v

Figure 1 is; a sideselevatlonal view partly in section ofqa portion 'fofgan vaxlehousing constructed according toaipreferred'embodiment of;

the invention;

Fi ure 2jis ialPHLt i-QIL topgplan viewlof part of theiaxle housing of Figure -1, with1the difierential bowl and;difierentialccarrier'attached;

. Figures; :isyasectiona-lwiew onfthe line --33 of Figure 1 yillus'tratinggthe shousing shape at apart formed to accommodate :insertion: of the differentialrgearin'g;

h'Figure 4 *is;-a:cross;-sectional view onrline 4-4 of s Figure :1 illustrating the ;-'integral thickened:

housing fiangetof the axleroffiigure 1; l

Figure5 tisrfa Ipartialase'ctional view on line 5-5 of Figure :1 illustrating ftheaxle-thousing contour having gradually curved corners intermediate the housing fiange and thespring seatiportionshown in Figurefi;

Figure 6 :is 'an 'enu-view substantiany along line 6 6 of Figure 1 and especially --illu's'trating the axle 'lioii'slngsliap'e at tIie-iiitegraL'spring seat parades;

Figure -7 is senseless-1m nanneal bearing sleeve for use in the axle housing of Figure-'1 is -an lev lonpartly in sectionof a portioniof anaile gedsstrucauaeeoramg to a runner embodiment of the invention;

I v vatior'ialyiew'of'aseparate 'hoiis'ing neevet s adapted to be secured to an agile housing center 'se'ction' as illustrated in Figure"8;, H r v H r'igure 11 is esetich bniiin'e lr-rrin Fisrel z "Figure 12 is aside elevation of the center; section ohan axle housing of the type illustrated 'in iFigure"8"nH p Q I g Figure 13 isla iiartial illan viewof the aiile housing tester s'etion orf'igti'rieirafartly broken away. insertion, and. having. ;ia1ne nusrsaw1 and'gear' carrier attached thereto.

A preferred embodiment of the invention is illustrated in Figures 1-7 wherein the axle housing essentially comprises a center section A, spring seat portions B and housing sleeve bosses C. Wheel bearing sleeves D are mounted in the housing sleeve bosses and project therefrom.

In this embodiment jot theinvention bosses C are integrally fiirmediw ith housing; center section A, the originally substantially rectangular contour of the housing center section being formed into the necessary circular cross section at the bosses by suitable forging operations.

Preferablyalso- -in' this embodiment of the inventiomthe axle housing is made from two blanks specially formed to provide upper and lower housing members 251 and 2| of steel which are substantially er thesame size and mirror images of each other and are joined along their contacting side wall edges by butt welding, the line of weld being indieated at 22 ina-Figure -1.;

Upper housing inember-20 is integrally. formed with thickened opposite, side flanges 23 1 and?! surrounding the upper halfoithe enlarged di iferential gear space opening indicatedatli as illustrated in Figures 1-; 2, S and; 4, special integral spring seat regions at ll; havingmaximum flat surface available; for attachment -:ofspring members, and terminates at oppositeendsin integral thickened half-cylindrical. housing'sleeve boss portions 2L Sincesonly one end-o f the housing is illustrated in figure :-1-,-only one spring seat region 26 and-one integral housingsleeve boss -21 is therein shown 'but itwill-beunderstood that both sides of the-'axle-shous-ing are the *same in this respect,

Lower housing members isl -similarly formed withopposite integral :thiokened-sidefianges 28 and 29 surrounding the lowerhal'f of the :difierential space opening =25 and: hat spring sea-tregions 3 Q, and terminating at opposite ends in-integral thickened half-cylindrical--housing sleeve bosses 32, I v

Asillustrated :in-Figures -1 and-3,--the-thickened side 'flanges v about openin -25 mayha ve small portions, indicated-;atai3- and Removed for ac- :bow'ed nud point portionand in the portions between the bowed portioni'and the-spring seatreg'ions by teaser of the-preliminary :sta'rnpi-ng -01 pressing operation formingf-the bowed center section, 's'ui'ta'bly 'rfenileifed fmore nearl s rectangular in crosssection at the-spring seat regioiis to provide'theireo uired'flat'spring seat ar'ea.

The somewhat rounded Ycorner contour of the housing member illustrated in-Figure 5 -is converted to 'the relatively s arp c'ornered spring s at Centaur illustrated has in Figure 6 by suitable forming operations tobe described.

In. turn, the rectangular 1 housing contour--out- 'wafdly'offtl'fefspiiifg seatsBis suitably converted toth'e cylindrical housing nsle'eve boss 'forr'nations at c. It'will'b'efnote2i ltlia'tlthe we-i1 ithicknesset th springjseat pciticns i'sTaboiit tnel's'ameas the thickness of the musing walistnrebetwne cent the "side flanges. Arse itlieicyli'n drical walls 'bf the insuring neewgtdsss are recnsiaereuy thickerthah'tlie remaining iiqusingwaus; except the side'nangesfwfiicn'afie cr mson the sa e housing portions indicated at 35 between the spring seats and end bosses are of gradually re-, duced external size and gradually increased wall thickness outwardly merging into the bosses. A preferred forming operation for obtaining this integral thickened boss formation will be later described herein.

The upper and lower housing members, with their bowed center portions, flat spring seats and thickened end bosses formed thereon, are assembled and welded together along line 22 to provide a permanently bonded axle housing wherein opening 25 is surrounded at opposite ends by fully circular flanges 23, 28 and 24, 29; and the part cylindrical end bosses 21 and 32 cooperate to provide uninterrupted cylindrical bores 36 at each end of the housing.

Wheel bearing sleeves, which in the preferred embodiment are relatively short hollow steel cylindrical tubular sleeves 31 each having a threaded outer area 38 for receiving a bearing securing nut, are fixed in bores 36 against both rotation and axial displacement. As illustrated in Figure 1, the inner end of each sleeve 3'! terminates substantially at or just beyond the inner end of its bore 36, so that the wheel bearing sleeves have but short unit support on the axle housing. This is a considerable improvement and saving in the length of wheel bearing sleeves which in prior constructions it was considered necessary to extend much further into the axle housing for additional lateral support within the housing. I attribute this unexpected efi'iciency of my improved construction to the overall combination of the short sleeve with the relatively heavy surrounding end boss and associated housing construction. In practice, I have discovered that the length of the bore 36 supporting sleeve 31 should be substantially equal to the sleeve length projecting and overhanging from the housing end for best service. For example, in a commercial embodiment of the invention, I employ a wheel bearing sleeve of about three and one quarter inches outside diameter and seven-sixteenths inch thick and about eighteen inches long, fixedly support-ed uniformly over about nine inches of its length by surrounding bore 36, the wall thickness of bore 36 being about three-fourths inch. These relations and relative dimensions hold whether the housing sleeve boss is integral with the center section of the housing as in Figures 1-7, or a separate member welded thereto as in Figure 8 later to be described.

Brake adapter flanges 39 fit snugly over the exterior of bosses C and are welded thereto in proper location as indicated at 4|. Each flange 39 is preferably an integral annular member which functions to hold the upper and lower housing members together against tendency for separation on weld line 22. These integral brake adapter rings therefore materially increase the overall strength of my axle housing in this embodiment of the invention.

, Each cylindrical housing sleeve boss terminates in a reduced annular shoulder indicated at 42 which is preferably machined out of the boss after tht two housing members have been welded together. Shoulder 42 provides a seat for a suitable wheel bearing retaining element (not shown). The outer corner of each shoulder 42 is rounded off as illustrated for safety in handling.

As illustrated in Figure 2, a differential bowl .43 and a difierential gear carrier 44 are fixed to opposite sides of the housing center section. In practice, bowl 43 may be bolted to housing side flange 23, 28, as by suitable. bolts, (not shown) passing into threaded apertures such as 45in the flange, but preferably bowl 43 is welded to flange 23, 28 since it is normally not removed during service, in which latter circumstance apertures 45 would not be necessary.

However, since gear carrier 44 must be removable in service, it is bolted to flange 24, 29, a series of bolts 46 passing through a carrier flange 41 mated with flange 24, 29, and the latter being provided with suitable threaded bolt receiving apertures 48 as shown in Figure 6.

According to an important phase of the invention, flanges 23, 28 and 24, 29, or at least carrier support flange 24, 29 which has a load bolted thereto, are-,of sufficient width, thickness and metal content as to accommodate the required number of threaded bolt receiving apertures and at the same time remain sufficiently rigid to withstand the loads and stressesnormally encountered at these parts of the axle housing. I have found, for example, that in an ordinary small truck axle housing formed from about onehalf inch sheet or channeled stock, a flange width of about one and one-half inches and a flange. thickness of slightly over three-fourths inch is satisfactory for securing a standard differential gear carrier thereto with three-fourths inch bolts.

My thickened axle housing side flanges are integral withthe housing so that prior problems of non-uniformly distributed attachment stresses are eliminated, and are equivalently self rigid and sturdy with the optimum sought to be ob tained in heretofore reinforced flange housings above described. No added flange reinforcement is needed for normal service. My novel axle housing construction is in this respect also much less expensive than prior reinforced housings since the time, equipment and labor of welding operations are eliminated and replaced by special forming operations which can be cor"- related closely to the preliminary forming oper-' ations.

In fabricating the axle housing of Figures 17, each housing member is made from a sheet steel blank of about three-sixteenths to onehalf inch in thickness.

Starting with a flat blank of sheet metalof the required length and containing the required amount of excess metal, the blank is first formed into a channel section substantially of the shape ilustrated in Figure 5. At this intermediate stage, the blank has excess metal at its end portions and has excess metal at its center portion, the excess metal being mainly in the side walls of the channel section. Thus the blank used in the invention contains more metal in its channel side Walls than a blank such as used in the above-mentioned Wilber and Alden patents for example. This original channel section has rounded corners best illustrated in Figure 5, curved on concentric arcs of which the inner arc has a radius not less than the thickness of the material in accordance with standard forging practice.

A further operation deforms the center or intermediate portion of the blank, bowing it outwardly to the arcuate shape shown in Figure 1 to provide one half of the differential opening 25 in the side walls of the blank. Either during this operation, or during subsequent and associated forging operations, the excess metal on the marinas side walls of -tha centen'se'ction of the blank is forced or swedgedinivardly-- by suitable forging dies: untilhousing side flanges containing excess metal are---formed-: Then; by-a sui-table-stoui-ngnp operation the sectional shape of I thablank -at the spring seat region is changedfrom that: illustrated= in- Figure-- tothatdllustrated in Figure 6, in which the corners-of 'the channel section are substantially square, 2 very small: radius being permitted 1 to-avoid over strainingor crack ing of the material attire-corners. This condition-extends longitudinally for adistance-somewhat greaterthanthe width of-the-springs which are to be mountedon the axle housing and prorides fiatspri-ng seats of the required area as indicated at 26 and 3 l, which aredirectly-- avaih able formounting-the springs. Ithas previously been considered necessary 'tmweld pada or-plates onto the axle housing-in order tuprovideasufii c-ient area fcr the" spring seats tokeep-the-axle housingfrom twisting or turning inthe u-bolts or other connections which secure it tothe springs; Withthis improvedconstruction; the surface area of each-- axlehousing; itself is made of; sufficient widthand L area to provide an adequate springseat, and; the springs may" be clamped directly to thehousingby--the-conven tional Ll bolts and apertured plates orother desired'means: By; providing some excess metal atthe spring seat-regions of theblank-and-swed e ing it down to form substantially squareconnered thickened and reinforced housing portions, the necessity of providing separately 1 forged or shaped spring seat plates and hand-welding-them tdthe, housing is avoided and'the spring-seats are permanently disposedin exactly-the rightlocation.

The housing side walls of the bowedintermediate portion orthe blank, and the excess 'metal'therein. provided are also swedged down by suitable forging action to form thickened'integral housing side flanges of the requiredthicke ness andother o dimensions surroundihgthe. cor responding portions of the differentiali opening, 25. As most clearly shown in Figure 4, in, this operation the excess metal forms .external1y p-to-' iecting flanges v ontheside walls ofthenhousing sections, the,.bolting faces ofwhich may beaacr: curately finished to lie in planesiwhich are eie actly parallel 1 with the longitudinal vaxis. 013. the housing. Thus: the dififerential ear carrier max bequicklymounted on the fiangesiiliandiflsand correctlycentered with-respectto theaxie b01155 ing This operation may beg-continuous with or subsequent to formation of the housing side flanges- InIat least some casesasiabove indie cated, it, may be necessary to provide; notches as indicated at 33- and 34'.-in:these;rein;forcing. rings 5 or: fiangesnin order to; permit. insertion; ot the differential gear mechanism into, opening 25: The thickened rings; or flangesqhowener; are made ;ofgs,uch size that suflicient matezialiremar ns even at the notched EDOItiOIlS-stO provide adeduate strength and rigidity for therstructure; Prefer? ab1y,-,aiter the housing center section andzspring seatzregions. have been formed; thezbliank isssuits ably formed to reduce it to the ,regui'redilength and convert the. excessmetal. intolthes required thickened end bosses. Thisdsdone byasuitable forging operations which convert-.the rectaneular blank; cross-section at. the blank; ends into i therequired halfrcircular crossasection: white-i atithe same: time holding. the blanhagainsh longitudinal movement I and 2 swedgingi its-endsinwardiy until the required wall thickness and shape is obtained inthe- -bosses. i I 7 After: members 2 B and 31 a have been :welded :together, w-heel bearing sleeves, Dare inserted the proper distance and non-rotatably: securedtwlthq in-bores 36-, preferably by packing the-sleeves in Dry Ice prior to insertion and letting them normalize andexpand into tight gripping: contact with the'walls-of boresifi.

While-the above described axle housing is pref:- erablymade from two similar-blanks, it-iS-With in the-scopeof the invention to makeit fromany desired number of similar blanks which may: be welded along contacting longitudinal I faces asaat 22-;

In someaxle assemblies it maybadesirable to make the two housing sleeve-bossesasseparate units and butt-weld them to the opposite ends ofthe assembled center section, 3;S-Wil-l be disclosed inthe further embodiment Of'thEJKb vention illustrated in Figures 8-13:

Each such housing sleeve boss unit, generally indicated at 56 in Figure S; is an integral hollow cylindrical member formed with 1 atruly cylindrical throughbore 5i and prov-ided at-its outer end with an external annular shoulder-52 which relieves the sharp edge thatwould otherwise-be present and also provides a-seatior a suitable wheel bearing retainingelementinotillustrated) Atdts-innerend, each boss is converted from a circular cross-section to the-substantially -rectangul-ar cross-sectional illustrated i in- Figure 1-0 to provide: an end region 53 thatcorrespondsin cross-section, size and wall thickness to-the end of 1 housingcenter section Ed to which it is -=to be welded and which is illustrated in Figural- In shaping region 53 of the boss'unit; th'e h'ol lowcyL drical tube comprising the bossis pref erablyu-pset and externallyreshapedat itsinner end i by suitable forging operations until region 53 comprises athickened wall section having required external shape andsize; Then excess metal. I is removed out- 05 the thickened end ot th'e. tube as indicated at 55 until the=-latter presents: the substantially rectangularcontour of Figure 1O: matching the adjacentend'of center section insize shape and wall thicknesss The inner endface 55 of bossuni-tfill is machined flat aepla-ne: at right angles to the :axis of it h8= boss:

Asillustrated in Figure 11, care is taken during this operation that the wall thickness theeintermediately shaped section 51 between a the cy lindricalpart of boss fiiiand region-53 is:at-1east equal to the Wall thickness-of the remainder of boss 55; and ipref eraply the sl-ope of wall 51' sb10u1d notbe more than sixty degreeato the axis-:of the boss for optimum strength.

Boss-unit 58 isprovided with a-brake adapter flange 58 which may beintegral therewith as il lustrated in Figure 8; or aseparate element welded thereto as in Figure 1.

' Housing center section 5 l is preterably =composed of two similar housing members 58 and 6B; which are joined by welding along line 6-! corresponding to line 22 i in Figure 1.- r The integral thick housing side flan ges E2: and 63 a-re preferably formed on housing members 1 59-1 and 1 6B-- in thesame manner that flanges- 23, 28'-and= 24; 29 are formed on thehousing members in- Figured: Similarly the end regions Stand 65 0f housing centersection 5 3 are formed in housing members M a-11d i 6 0*- to the substantially rectangular: contour illustrated. Figure 9 is made by formingopovations as inmembers 20" and 21" of Figure 1. End-= regions -66 and Bi -are of sufilcient longitu 9 dinal extent and flat area to provide spring seats similar to seats 26, 3| in Figure 1. Thus, in general, center section 54 of Figures 12 and 13 is the same in structure and method of construction as the axle housing of Figure 1, except for the housing sleeve bosses of the latter.

In making the axle housing of Figures 8-13, after the two housing members 59 and 63 have been formed to provide their integral thickened flan e portions surrounding the differential opening and integral stoved-up spring? seat portions, they are positioned in assembled. relation, as illustrated in Figure 12, and their contacting edge portions permanently welded together along line H. I

The opposite end faces 65 and 61 ofcenter section 54 are machined smooth and in planes perpendicular to the longitudinal center line of the housing. Then a housing sleeve boss unit 50 is permanently welded to each end of the center section, faces 56 and E6 (or 61) being matched together and then joined by a butt-welded, as at 68 in Figure 8. A wheel bearing sleeve 31 is then suitably secured within each boss as in Figure 1 to constitute the complete axle housing.

Although it has been found desirable from considerations of present manufacturing equipment, to form the housing center section in two similar parts and unite these parts by welding along adjoining edges as above described, it is within the scope of the invention to form housing center section 54 from a single tubular blank. The blank would be longitudinally split at its center portion and expanded by suitable dies to provide the differential space and forged to provide the required thickened flanges about the opening at each side thereof. The ends of the blank would be suitably formed to the proper cross-sectional shape for the spring seats, and the housing sleeve bosses 50 welded to the ends thereof. This construction 1 will eliminate the longitudinal welds along the plane of the line 6 l and provide an integral center section with integral reinforcing flanges around the differential openings and integral spring seat portions.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are thereof intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A metal axle housing member comprising a central arcuate body section and sections extending laterally in opposite directions from said body section, each of said laterally extending sections being of general rectangular form in cross-section and including a forged spring seat portion having substantially square corner regions of reater thickness than the angularly related walls thereof and containing metal displaced thereinto during said forging, and each said laterally extending section also including an intermediate connecting portion between said body section and the spring seat portion having Walls and rounded corners of substantially uniform thickness.

2. A hollow axle housing comprising two longitudinally similar channel members permanently bonded together along longitudinally coexten- 10 sive edges, each of said members comprising end portions joined by a bowed center portion span-'- ning a drive mechanism receiving space, with the walls of said members along the edges of said bowed portions thickened to provide strong integral attachment flanges, said end portions each havingv outer .end regions forged into substantially rectangular cross-section with substantially square corners that are thicker than the adjacent housing walls andsaid outer end regions serving 'as spring attachment seats, and said spring seat regions being integrally joined to said bowed portions byintermediate regions having walls and rounded corners of substantially uniform thickness.

3. A hollow axle structure comprising-two longitudinally similar channel members permanent-J ly bonded together along longitudinally coextensive edges, each of said members comprising end portions joined by a center portion, said end portions each having outer regions formed into substantially rectangular cross-section with substantially square corners that are thicker than the adjacent walls and said outer regions serving as spring attachment seats, and said spring seat regions being integrally joined to said center portions by transition regions merging from said spring seat region walls to walls and rounded corners of substantially uniform thickness.

4. The axle structure defined in claim 3, wherein each of said end portions of said channel members terminates outwardly in an integral semicylindrical boss.

5. An axle structure comprising a hollow memher having end portions of substantially rectangular cross section and a central portion connected by transition regions to said end portions,

each of said end portions including a. spring seat region having substantially square corners providing a flat spring attachment area with said corners being materially thicker than the adjacent walls of said member, and said transition regions merging from said substantially rectangular square cornered cross section into a substantially rectangular section with rounded corners and walls of substantially uniform thickness.

6. The axle structure defined in claim 5 wherein the end portions of said hollow member are formed outwardly of said spring seat regions with integral substantially cylindrical bosses.

'7. A metal axle housing member comprising a central arcuate body section and sections extending laterally in opposite directions from said body section, each of said laterally extending sections being of general rectangular form in cross-section and including a forged spring seat portion having substantially square corner regions of greater thickness than the angularly related walls thereof and containing metal displaced thereinto during said forging, and each said laterally extending section including a semi-cylindrical bearing receiving terminal portion having a wall thickness exceeding the thickness of the walls of said spring seat portion and integrally merged therewith.

8. An axle member comprising a central body section of general rectangular form in cross-sec tion and provided with an outer spring seat portion having substantially square corner regions of greater thickness than the angularly related walls thereof, said central body section including a connecting transition portion between said central body section and the spring seat portion having walls and rounded corners of substantially uniform thickness.

9. -.A-.n.axle member comprising a central body section ofgeneral rectangular form in cross-section and provided with spring seat portions having sobstantiallysquare corner regions of greater thickness than the angularly related walls there- OLsaid' central 'body section including cylindrical bearing receiving terminal portions each having a wall thickness exceeding the thickness of the walls of the adjacent spring seat portion and integrally merged therewith.

Y-LAW'RENCE R. BUCKENDALE.

"REFERENCES CITED Theiollowing references are of record in the this patent:

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